Bioreactors and Obtaining Foreign Gene Products in Biotechnology
Bioreactors are specialized vessels that are designed to provide optimal conditions for the growth of microorganisms that are used in production of foreign gene products. Bioreactors help to maintain optimal conditions like temperature, pH, nutrients, and oxygen. This ensures maximum production and better quality of products. In recombinant DNA technology, bioreactors are key tools in large scale production.
This Story also Contains
- What are Foreign Gene Products?
- What are Bioreactors?
- Types of Bioreactor
- Steps in Obtaining Foreign Gene Products
- Applications of Obtained Foreign Genes
- Key Vectors and Enzymes in Recombinant DNA Technology
- NEET MCQs on Bioreactors and Foreign Gene Products
- FAQs on Bioreactors in Biotechnology
Biotechnology and its applications in bioreactor systems have transformed the pharmaceutical industry. It has made the production of products like medicine, agricultural fertilizers, and enzymes efficient as well as cost-effective. Learn their types, working, and role in recombinant DNA technology with NEET-focused mnemonics and MCQs.
What are Foreign Gene Products?
A foreign gene product is a protein or any other molecule produced by the host cell after a foreign gene is introduced by recombinant DNA technology. In this process, a gene from another organism is inserted into the genome of the host using vectors like plasmid. After the insertion, the foreign gene is expressed under appropriate conditions and desired product is obtained. This technique is widely used in medicine, agriculture, and industry to obtain desired products.
What are Bioreactors?
Bioreactor refers to the container used to conduct chemical reactions. It is a tool that assists in the mass production of culture. New biological products are created in the bioreactor with the assistance of various environmental cells, including plant, animal, and human cells. Some basics of bioreactors are discussed below:
The bioreactor is constructed of stainless steel and has a cylinder-like shape.
The basic stirred-tank bioreactor and the sparged stirred-tank bioreactor are the two bioreactors most suited for producing foreign gene products.
There are several different kinds of bioreactors, including continuous stirred tanks, fluidized beds, bubble columns, packed beds, photobioreactors, and airlift reactors.
Commonly Asked Questions
A bioreactor offers more control over environmental conditions than a culture flask. It allows regulation of parameters like temperature, pH, oxygen levels, and nutrient supply. Bioreactors also enable continuous culture, larger volumes, and often include systems for monitoring and adjusting conditions in real-time.
A perfusion system is a type of continuous culture where cells are retained in the bioreactor while spent medium is constantly replaced with fresh medium. This allows for very high cell densities and continuous product harvesting. It's often used for sensitive products or when high productivity is needed over long periods.
Types of Bioreactor
Traditional fermenters were made up of wood or slate. In recent years, stainless steel bioreactors are in use. Based on the design of the bioreactors, they can be grouped into the following types:
Types of Bioreactors | Explanation |
Batch Reactors |
|
CSTRs ( Continuous Stirring Tank Reactors) |
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Airlift Bioreactors |
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Photobioreactors |
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Steps in Obtaining Foreign Gene Products
The process of obtaining engine products is one of the very critical processes in the microbial biotechnology industry. This process uses the microorganism to produce the valuable proteins and metabolites which are essential for several processes. The steps are discussed below:
Isolation of the desired genes.
Location of the possible vector through which the desired gene will be carried out and inserted into the vector using ligase.
The entire process takes place and there is the formation of recombinant DNA.
After the introduction of recombinant DNA into the host such as a bacterial cell it resolved into the presence of foreign genes into the cell.
After some time of adaptation of the recombinant DNA, there is protein and metabolic synthesis that takes place through recombinant cells.
There is a large scale of cultivation done to obtain the desired product from the reactors
Commonly Asked Questions
Sterility is crucial to prevent contamination by unwanted microorganisms. Contaminants can outcompete the desired organism, alter the product, or create harmful byproducts. Bioreactors are designed to be sterilized (often by steam) and maintain sterility throughout the culture period. This includes sterile air filters, seals, and sampling ports.
Bioreactors use special ports for sampling and additions that can be sterilized. These often involve steam-sterilizable valves or septum ports that can be accessed with sterile needles. Some systems use automated sampling devices that can take samples without breaking the sterile barrier.
Scale-up involves increasing the volume of the culture while maintaining or improving productivity. It's a complex process that considers factors like oxygen transfer, mixing efficiency, and heat transfer, which don't scale linearly. Engineers use dimensionless numbers and modeling to predict behavior at larger scales and may need to redesign aspects of the process for optimal performance.
Challenges include maintaining efficient oxygen transfer, ensuring uniform mixing without excessive shear, controlling temperature in larger volumes, and managing increased metabolic heat production. Additionally, the behavior of organisms can change at larger scales, and contamination risks may increase.
Computer control systems integrate data from sensors, control process parameters, and can adjust conditions automatically. They allow for precise control, data logging, and often include alarms for out-of-range conditions. Advanced systems may use predictive models or artificial intelligence to optimize processes in real-time.
Applications of Obtained Foreign Genes
Some basic uses are discussed below:
The creation of secondary metabolites such as lovastatin, penicillin, and cyclosporin-A.
Production of dairy products that undergo fermentation, such as cheese, buttermilk, yoghurt, etc.
The process through which citric acid, lactic acid, acetic acid, and other organic acids are produced
production of vital enzymes such as lipase, xylanase, and laccase
In some cases, the creation of microbial cells rather than their end products takes place in bioreactors. This is seen in the creation of yeast, lactobacillus, single-cell proteins, etc.
Mammalian cells are also cultured in bioreactors.
Photobioreactors are used to grow algae and cyanobacteria for biofuels, bioplastics, nutraceuticals, and other products and treat wastewater.
Key Vectors and Enzymes in Recombinant DNA Technology
It takes effort to remember everything in a single go. We made the entire problem easy. Some of the tricks regarding obtained foreign genes/ recombinant genes are given below which you can use to memorise the important points.
Key Steps in Recombinant DNA Technology
"GIVERC": Gene Isolation, Vector Selection, Insertion, Transformation, Expression, Recovery
G: Gene Isolation - Extracting the desired gene from the source organism.
I: Insertion - Using ligase to insert the gene into a suitable vector.
V: Vector Selection - Choosing an appropriate vector (plasmid, virus) that can replicate within the host.
E: Expression - Introducing the recombinant DNA into the host cell and allowing the expression of the desired protein.
R: Recovery - Isolating and purifying the desired protein or product from the host cells.
C: Confirmation - Verifying that the foreign gene has been successfully integrated and expressed.
Types of Vectors
"PVB: Plasmids, Viruses, BACs"
P: Plasmids - Circular DNA molecules commonly used in bacteria.
V: Viruses - Can be engineered to carry foreign DNA and infect host cells.
B: BACs (Bacterial Artificial Chromosomes) - Useful for cloning large fragments of DNA.
Important Enzymes in Recombinant DNA
"REPL: Restriction enzymes, Ligase, Polymerase"
R: Restriction Enzymes - Cut DNA at specific sequences to isolate genes.
E: Ligase - Joins the DNA fragments (insert and vector) together.
P: Polymerase - Amplifies the DNA during the cloning process.
Applications of Recombinant DNA Technology
"MAPS: Medicine, Agriculture, Pharmaceuticals, Science"
M: Medicine - Production of insulin, vaccines, and gene therapy.
A: Agriculture - Development of genetically modified organisms (GMOs) for higher yield.
P: Pharmaceuticals - Synthesis of hormones, antibodies, and enzymes.
S: Science - Research tools for genetic studies and biotechnology.
NEET MCQs on Bioreactors and Foreign Gene Products
Q1. _______is a stainless steel vessel that provides a sterile environment and contains the growth medium for obtaining the foreign gene product.
Bioreactor
Feeding pump
Submerged Aerator
Sensor probes
Correct answer: 1) Bioreactor
Explanation:
The bioreactor is made up of various components, including "an agitator system, a foam control system, a baffles system, a pH & temperature control system, a fermenter vessel, an aeration system, and an impeller system. Each of these components is required for the operation of the bioreactor
Hence, the correct answer is option 1) Bioreactor is a stainless steel vessel that provides a sterile environment and contains the growth medium for obtaining the foreign gene product.
Q2. Sparged stirred-tank bioreactors have been designed for______.
purification of the product
addition of preservatives to the product
ensuring anaerobic conditions in the culture vessel
increased surface area for oxygen transfer
Correct answer: 4) increased surface area for oxygen transfer
Explanation:
The surface area for oxygen transfer in a sparged stirred-tank bioreactor is greater than that of a simple stirred tank. Purification and addition of preservatives are associated with downstream processing. The surface area for oxygen transfer in a sparged stirred-tank bioreactor is greater than that of a simple stirred tank.
Hence, the correct answer is option 4) increased surface area for oxygen transfer.
Q3. _________Bioreactors are commonly used for the industrial production of biological products.
Stirred-tank bioreactors
Sparged stirred-tank bioreactor
Piston flow bioreactor
Membrane bioreactors
Correct answer: 1) Stirred-tank bioreactors
Explanation:
Stirred tank bioreactors (STBRs) are the most commonly used reactors for cultivating biological agents such as cells, enzymes, or antibodies. They are contractors where the well-mixed among stages is achieved primarily through internal mechanical agitation.
Hence the correct answer is option 1) Stirred-tank bioreactors.
Also Read:
FAQs on Bioreactors in Biotechnology
Define bioreactors.
Bioreactor is a fermentation vessel which is used in the synthesis of numerous chemicals, and biological processes. In order to remove the waste biomass of cultivated microorganisms as well as their products, it is a closed container with suitable conditions for aeration, agitation, pH, and temperature.
What are the main types of bioreactors?
The types of fermentors or bioreactors used in industry are -
Continuous Stirred Tank Reactor: In a CSTR, one or more agitators are supported by a central shaft powered by a motor. Gas distribution is improved by the sparger and impellers.
Airlift Reactor: It is also known as a tower reactor. It has an airlift system, the fluid volume is divided into two zones to increase oxygen transfer, and circulation.
Photobioreactor: It is a specially designed fermentation machine that receives natural or artificial light. It is made up of translucent material which promotes photosynthesis.
What are the basic steps in obtaining foreign gene products?
To obtain a foreign gene product:
Insert a piece of foreign or desired DNA into a cloning vector.
Transfer it into the host cell.
The alien DNA gets multiplied.
The cell containing the foreign gene is cultured in appropriate medium at optimal conditions in a bioreactor to induce the expression of the target product.
The culture is used to extract the desired product and purify it using separation techniques.
What are some examples of products obtained from foreign genes?
Products that are obtained from foreign genes are generally produced through recombinant DNA technology. A gene of interest is inserted into the host organism like bacteria, yeast, or plant cells. The gene gets amplified and later is extracted and purified. Examples include, human insulin is produced using recombinant DNA in E.coli for diabetes. Human growth hormone helps to treat disorders related to growth and development.
Frequently Asked Questions (FAQs)
Strategies include optimizing media composition, using fed-batch or perfusion systems, genetic engineering of the production organism, controlling metabolic fluxes through process conditions, and implementing advanced control strategies based on real-time monitoring of metabolites or product formation.
Large-scale bioreactors use cooling jackets or internal cooling coils to remove heat. The cooling system capacity is a critical design factor. Some designs use external heat exchangers in a recirculation loop. In extreme cases, evaporative cooling by allowing some of the water to evaporate can be used.
Mixing time is the time required to achieve homogeneity after adding a substance to the bioreactor. It's crucial for ensuring uniform distribution of nutrients, oxygen, and pH control agents. Shorter mixing times generally indicate better performance but must be balanced against increased power input and potential shear damage to cells.
Single-use bioreactors use disposable plastic bags or vessels instead of fixed stainless steel tanks. They eliminate the need for cleaning and sterilization between batches, reducing turnaround time and cross-contamination risks. However, they're limited in size and may have different mixing and gas transfer characteristics compared to traditional reactors.
CFD uses numerical analysis to simulate fluid flows within the bioreactor. It helps in optimizing designs for mixing, oxygen transfer, and shear stress distribution. CFD can predict the performance of new designs or scale-up scenarios, potentially reducing the need for extensive experimental trials.
For secreted products, the bioreactor design focuses on optimizing the culture environment for production and secretion, with considerations for product stability in the medium. For intracellular products, the focus is on maximizing biomass production, and the bioreactor must be designed with cell harvesting and lysis steps in mind.
Challenges include ensuring proper protein folding, preventing degradation by proteases, optimizing codon usage for the host organism, managing metabolic burden on the cells, and developing efficient purification strategies. The bioreactor conditions must be optimized not just for growth, but for protein production and quality.
Bioreactors can use selective pressure (like antibiotics) to maintain plasmids, but this is often not feasible at large scales. Alternative strategies include using well-designed selection systems, integrating genes into the host chromosome, or optimizing culture conditions to reduce the metabolic burden of plasmid maintenance.
Strategies include using tolerant or engineered strains, implementing in situ product removal techniques (like extraction or adsorption), using fed-batch or continuous cultures to control product concentration, and optimizing process conditions to balance growth with product formation.
OTR is a critical parameter that determines how quickly oxygen can be supplied to the cells. It's influenced by factors like agitation speed, air flow rate, bubble size, and medium composition. Understanding and optimizing OTR is crucial for scaling up processes and ensuring that oxygen doesn't become limiting in high-density cultures.